Dance lessons, in particular — perhaps because they incorporate exercise, social interaction and learning — have a positive effect on a brain region called the fornix, said the study’s author, Aga Burzynska, an assistant professor in Colorado State University’s human development and family studies department.

The fornix connects the hippocampus to other areas of the brain and seems to play an important role in memory: Changes in the fornix have been linked to progression from mild cognitive impairment to Alzheimer’s disease.

To study the effects of different forms of exercise on the brain, Burzynska and team followed a group of 174 healthy adults ages 60 to 79 over four years. They met three times a week for the first six months in a gym at the University of Illinois at Urbana-Champaign. The rest of the study involved follow-up screenings.

The participants were assigned to one of four groups: One group did aerobic walking, a second group did the same aerobic walking and took a daily nutritional supplement, a third group attended stretching and balance classes (as an active control group) and the fourth group took the dance classes.

The dance classes involved choreographed and social group dances that challenged participants’ cognitive and motor-learning abilities. Each participant also underwent MRI screenings at the beginning and end of six months that measured white matter microstructure.

White matter is akin to the brain’s wiring. As people age, the quality of that wiring deteriorates, causing disruptions in the transmission of electrical messages in the brain. And since those electrical signals are how our brain cells communicate, this deterioration becomes a critical impediment for brain function. It’s been unclear whether this age-related decline in white matter is unalterable or could instead be slowed or even reversed.

Burzynska’s team found that integrity of the fornix increased in the dance group. And the test subjects who took dance classes during that time saw improved white matter integrity in an area of the brain related to memory and processing speed ― while the subjects who did other forms of exercise in the study did not.

This led to two important conclusions: One, the decline in the brain’s white matter can actually be detected over a period of only six months in healthy aging adults, much faster than previous studies have shown. And two, while the white matter declines were noted on the MRI, they were not apparent in cognitive performance, which was measured through standardized tests that included vocabulary and visual comparisons. Almost everyone performed better after six months of exercising in any form than they did at the study’s start.

These results indicate that there could be a time lag between when the brain changes structurally and when we start having trouble thinking and remembering, Burzynska said.

Far more encouraging was that the results showed that engaging in “any activities involving moving and socializing,” as each of these group programs did, can improve mental abilities in aging brains.

“The message is that we should try not to be sedentary,” she said. “The people who came into our study already exercising showed the least decline” in white matter health, she pointed out, and those who took up dancing showed white matter gains.

Studies have long connected physical exercise to improving brain health. In one study done at the University of British Columbia of 86 women ages 70 to 80 with probable mild cognitive impairment showed that aerobic exercise increased their hippocampal volume, which is an important predictor of memory function.

This research comes at a critical time. Researchers say one new case of dementia is detected every four seconds globally. They estimate that by 2050, more than 115 million people will have dementia worldwide.

The finding was published March 16 in the journal Frontiers in Aging Neuroscience.